Meters for making electrical measurements by contacting points to be measured with measurement probes are well-known. An example of such a known meter is a digital multimeter. Conventionally these meters indicate the measured value on either an analog or a digital visual display while the measurement probes are in contact with the points to be measured. Consequently, they require that the user view the display in order to read the measured value while the measurement probes are in contact with points to be measured.
In recent years, the electronics industry has tended toward high-density electronic circuits. In such circuits the electrical parts and connections are physically mounted close together to reduce the overall size of the circuit. These high density circuits often require electrical testing by measuring the voltages, currents or resistances of various points in the circuit with a meter to verify proper operation. The physically small size of the parts requires test personnel to accurately manipulate the meter's measurement probes to make contact with portions of the circuit. This manipulation is often difficult even if the operator is viewing the meter probes and the measurement point at the time when contact is made.
However, viewing the display of a conventional meter requires the operator to take his eyes off the measurement point in the electronic circuit. Sometimes the operator must physically move his head to view the measured value. Often in viewing the display after placing the meter probes on the points to be measured, the probe slips off the measurement point before the display is viewed thus preventing an accurate measurement. Therefore, efficency and accuracy in the measurement operation is reduced. The higher the number of the measured points, the greater the influence.
In addition, meters provided with a analog or digital visual displays have the drawback that it is difficult to read measured values if there is insufficient illumination.
Accordingly, it is an object of this invention to provide a meter which allows the operator to read the measured value without taking his eyes off the measurement point.
It is a further object of the invention to provide a meter which allows audible readout of the measured value.
It is yet another object of the invention to provide a meter which allows visual readout of the measured value in addition to audible readout.